Current personal computers typically include a mouse, which is a device that is manually rolled across a surface to position a cursor on the computer screen. A mouse pointing device typically incorporates a track ball or other surface engaging mechanism which rotate disk encoders to generate positional data. Mouse devices also include push-buttons which may be actuated by the operator's fingers to facilitate such actions as menu selection and the dragging of images across the screen.
Mouse devices are known that incorporate an optical scanner so that images may be captured from a document and transferred to the computer by manually sliding the scanner across the document. U.S. Pat. No. 5,355,146, for example, discloses a mouse device that incorporates a linear image sensor such as a CCD. When used as a scanner, the device is dragged across a document and the image data captured in this manner is fed to software stored in the computer. The device may be freely dragged back and forth across the document several times and the software, responding to the continuously-monitored position of the device, continuously writes the scanned image data into the appropriate place within a random access memory. One limitation of this device is that it requires complex software to properly correlate the image data with the positional data.